The bomb appeared to have been detonated by remote control and it went off as the police vehicle was driving through the village of el-Wefaq near the Egyptian border with the Gaza Strip, security officials said.

A medical official said the explosion also wounded two officers. All officials spoke on condition of anonymity because they were not authorized to speak to journalists.

The Egyptian military, aided by police forces, is carrying out an offensive in the northern Sinai, a militant stronghold where it has killed and captured dozens of suspects in recent months.

The country has been battling an Islamic insurgency in the area for years, but violence there dramatically escalated after the military’s ouster last July of Islamist President Mohammed Morsi and its subsequent crackdown on his Muslim Brotherhood supporters.

An al-Qaida-inspired group called Ansar Beit al-Maqdis has claimed responsibility for a series of explosions and suicide attacks over the past year, mostly targeting police officers and soldiers. The group claimed its attacks were revenge for the crackdown.

On Sunday, troops raided the village of el-Wefaq, killing six militants, officials said. Also on Sunday, a leading member of Ansar Beit al-Maqdis was killed during clashes with security forces in el-Arish, the provincial capital of northern Sinai, authorities said.

Meanwhile, military spokesman Mohammed Samir said a stampede Tuesday among the families of military cadets rushing to enter their camp killed nine civilians. Samir said in a statement on his official Facebook page that a large number of visiting families gathered outside the camp in the Suez Canal province of Ismailia, causing the stampede when the doors opened for the visit.